To continue our research on the physiological correlates of sexual behavior in male cats we now plan to investigate the effects of lesions in the primary olfactory areas and major limbic structures. In a previous study we found that complete removal of the olfactory bulbs did not cause any decrements in mating behavior in sexually experinced males. Rather, there was a small but consistent increase in sexual activity. We now plan to see if there is a relationship between this increase in sexual activity and the well-known hypersexuality reported in male cats following lesions in the amygdala and/or pyriform cortex. However, there were major methodological weaknesses in the latter studies in the ways in which hypersexuality was assessed which make these studies difficult to interpret. Emphasis will be directed to the development of special quantitative tests to measure the purported increase in objects (animate or inanimate) that operated males will attempt to mate with. We also anticipated that lesions in other structures of the limbic system will cause decrements or qualitative changes in mating behavior. These experiments should clarify the problem of hypersexuality generally, and specifically in relation to certain limbic strucures. The research should also contribute to a better understanding of the function of the limbic system particularly in respect to self- and species-preserving behaviors that have a strong basis in autonomic function.